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October 5, 2013

Investigational Vaccine Found To Reduce Norovirus Symptoms

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redOrbit Staff & Wire Reports - Your Universe Online

An experimental norovirus vaccine has been found to reduce the main symptoms of the gastrointestinal infection by more than half, according to research presented this week at the IDWeek 2013 infectious diseases conference in San Francisco.

The investigational vaccine, which reportedly appears to be generally well tolerated and effective against the most common strain of the RNA virus, has been found to reduce vomiting and/or diarrhea associated with the condition by 52 percent, according to lead author David I. Bernstein of Cincinnati Children's Hospital Medical Center and his colleagues.

Currently, there is no treatment or cure for norovirus, which is the leading cause of severe gastrointestinal infection in the US. It causes nearly 90 percent of all epidemic non-bacterial outbreaks of gastroenteritis worldwide and can affect people of all ages. It is usually transmitted by contaminated food or water, by person-to-person contact, or through aerosolization of the virus.

“Significant outbreaks occur in health care facilities, childcare centers and other places where people are in close quarters, including in the military and on cruise ships,” the Infectious Diseases Society of America (IDSA), sponsors of IDWeek 2013, said in a statement. “Each year, 19 to 21 million Americans – one in 15 – are infected and as many as 800 die, according to the Centers for Disease Control and Prevention (CDC). In addition, one recent evaluation reports that the overall cost of the disease in the United States is $5.5 billion annually.”

Bernstein and his colleagues conducted a randomized, multi-center study featuring 98 individuals who consented to drinking water contaminated with a significant amount of the virus. Fifty of those participants were injected with the vaccine, and the remaining 48 were given a placebo injection. Neither group knew in advance which group had received the vaccine and which group had not.

Twenty-six members of the vaccine group (52 percent) were infected, as were 29 members (60 percent) of those in the placebo group. Among those who did not receive the vaccine, which targeted the GI.1 and GII.4 genotypes of norovirus, 20 members (42 percent) suffered from mild, moderate or severe vomiting and/or diarrhea. In comparison, 10 (20 percent) of the vaccine group experienced those symptoms – a reduction of 52 percent.

“Norovirus truly is a global issue and most if not everyone has experienced it to some degree. The results of our study are promising and our next step is to test this vaccine in a real-world setting,” said Dr. Bernstein.

“If the vaccine continues to prove as effective as our initial results indicate, it could be used for specific populations or situations – in those at a higher risk of severe disease such as the elderly or at high risk for infection or transmission such as in day care, people going on a cruise, those in nursing homes or in the military,” he added. “Or it could be offered to everyone, since all of us are exposed at one time or another.”

Co-authors of the research include Robert L. Atmar and David Y. Graham of the Baylor College of Medicine; G. Marshal Lyon, of the Emory University School of Medicine; John J. Treanor, of the University of Rochester Medical Center; Wilbur H. Chen of the University of Maryland School of Medicine; Robert W Frenck and Xi Jiang of the Cincinnati Children's Hospital Medical Center; Jan Vinjé of the CDC, Mohamed S. AL-Ibrahim of Shin Nippon Biomedical Laboratories; Jill Barrett, of the EMMES Corp.; and Charles Richardson, Robert Goodwin, Astrid Borkowski, Ralf Clemens, and Paul M. Mendelman of Takeda Vaccines.